Laser processing of fabric for electronic devices

ABSTRACT

An electronic device such as a cover for a portable device or other electronic equipment may have circuitry mounted in a housing. The housing may be formed from layers of material such as fabric and polymer layers. The circuitry of the electronic device may include components mounted on a printed circuit. The components may include movable components such as keys in a keyboard. A fabric layer may overlap the keys. Border regions of the fabric layer that surround each key may be characterized by a stiffness. To ensure that the keys or other movable components in the device exhibit satisfactory stiffness levels, the keys can be tested and selected border regions or other fabric layer portions may be laser ablated or otherwise processed to locally reduce fabric layer stiffness.

BACKGROUND

This relates generally to electronic devices, and, more particularly, toprocessing fabrics and other materials for electronic devices.

Electronic devices such as computers, cellular telephones, and otherdevices include housing walls and other structures formed from materialssuch as plastic and metal.

The characteristics of electronic device structures such as housingwalls and other structures may be subject to unavoidable manufacturingvariations. For example, following an initial set of manufacturingoperations, a portion of a layer for an electronic device may be stifferthan desired. If care is not taken, manufacturing variations canadversely affect manufacturing yield. In the absence of suitable reworktechniques, parts may need to be discarded.

It would therefore be desirable to be able to provide improvedtechniques for fabricating electronic device structures.

SUMMARY

An electronic device such as a cover for a portable device or otherelectronic equipment may have circuitry mounted in a housing. Thehousing may be formed from layers of material such as fabric and polymerlayers. The circuitry of the electronic device may include componentsmounted on a printed circuit. The components may include movablecomponents such as keys in a keyboard.

A fabric layer in the housing may overlap the keys. Border regions ofthe fabric layer that surround each key may be characterized by astiffness. To ensure that the keys in the device exhibit satisfactorystiffness levels, the keys can be tested. If certain keys are too stiff,border regions surrounding those keys may be processed using lasers orother processing equipment. For example, laser ablation techniques orother processing techniques may be used to ablate portions of a fabriclayer, thereby removing fabric and reducing fabric stiffness in theborder regions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an illustrative electronic device inaccordance with an embodiment.

FIG. 2 is a cross-sectional side view of an illustrative electronicdevice in accordance with an embodiment.

FIG. 3 is a cross-sectional side view of an illustrative key for akeyboard in accordance with an embodiment.

FIG. 4 is a diagram of illustrative equipment of the type that may beused in processing structures for an electronic device in accordancewith an embodiment.

FIG. 5 is a cross-sectional side view of an illustrative electronicdevice structure having fibers embedded in binder material in accordancewith an embodiment.

FIG. 6 is a cross-sectional side view of an illustrative electronicdevice structure of the type that may include fabric and molded featuresin accordance with an embodiment.

FIG. 7 is a cross-sectional side view of an illustrative electronicdevice structure having a portion that has been removed using laserablation in accordance with an embodiment.

FIG. 8 is a cross-sectional side view of an illustrative stack ofelectronic device structures for an electronic device in accordance withan embodiment.

FIG. 9 is a side view of illustrative equipment for applying heat to anelectronic device structure with a heated element in accordance with anembodiment.

FIG. 10 is a side view of an illustrative laser-based tool forprocessing an electronic device structure in accordance with anembodiment.

FIG. 11 is a cross-sectional side view of an illustrative electronicdevice structure such as a fabric layer in an illustrative configurationin which the fabric layer is being processed on its outer surface inaccordance with an embodiment.

FIG. 12 is a cross-sectional side view of an illustrative electronicdevice structure such as a fabric layer in an illustrative configurationin which the fabric layer is being perforated in accordance with anembodiment.

FIG. 13 is a cross-sectional side view of an illustrative electronicdevice structure such as a fabric layer in an illustrative configurationin which the fabric layer is being processed on its inner surface inaccordance with an embodiment.

FIGS. 14, 15, 16, and 17 are top views of illustrative processingpatterns that may be used in modifying an electronic device structuresuch as a layer of fabric in accordance with an embodiment.

FIGS. 18, 19, 20, 21, 22, and 23 are illustrative border regionprocessing patterns that may be used to modify an electronic devicestructure such as a fabric layer for a key in a keyboard in accordancewith an embodiment.

FIG. 24 is a flow chart of illustrative steps involved in fabricatingelectronic device structures such as fabric-based structures usingprocessing equipment of the type shown in FIG. 4 in accordance with anembodiment.

DETAILED DESCRIPTION

An electronic device may have housing structures and other structuresformed from plastic, metal, and other materials. Some structures may beformed from layers of material (e.g., plastic, metal, and/or othermaterials). Other structures may be formed from intertwined strands ofmaterial (e.g., fabric).

Laser processing and other processing techniques may be used to processfabric structures and other structures for an electronic device duringmanufacturing. For example, fabric layers may be modified duringmanufacturing to adjust fabric stiffness and other characteristics.

A schematic diagram of an illustrative electronic device with structuresthat may be processed using laser processing techniques and othertechniques is shown in FIG. 1. Device 10 may be a tablet computer,laptop computer, a desktop computer, a display, a cellular telephone, amedia player, a wristwatch device or other wearable electronicequipment, headphones, an accessory such as a cover or other enclosurefor an electronic device such as a tablet computer or other portabledevice, equipment embedded in a larger system, or other suitableelectronic device.

As shown in FIG. 1, electronic device 10 may have control circuitry 16.Control circuitry 16 may include storage and processing circuitry forsupporting the operation of device 10. The storage and processingcircuitry may include storage such as hard disk drive storage,nonvolatile memory (e.g., flash memory or otherelectrically-programmable-read-only memory configured to form a solidstate drive), volatile memory (e.g., static or dynamicrandom-access-memory), etc. Processing circuitry in control circuitry 16may be used to control the operation of device 10. The processingcircuitry may be based on one or more microprocessors, microcontrollers,digital signal processors, baseband processors, power management units,audio chips, application specific integrated circuits, etc.

Input-output circuitry in device 10 such as input-output devices 12 maybe used to allow data to be supplied to device 10 and to allow data tobe provided from device 10 to external devices. Input-output devices 12may include buttons, joysticks, scrolling wheels, touch pads, key pads,keyboards, microphones, speakers, tone generators, vibrators, cameras,sensors, light-emitting diodes and other status indicators, data ports,displays, etc. A user can control the operation of device 10 bysupplying commands through input-output devices 12 and may receivestatus information and other output from device 10 using the outputresources of input-output devices 12. If desired, device 10 may becoupled to an external device (e.g., a host device or an auxiliarydevice) using a cable and/or a wireless signal path. In this type ofarrangement, device 10 may gather user input that is routed to thecoupled external device and may receive information from the externaldevice that is presented to the user with the output resources of device10.

FIG. 2 is a cross-sectional side view of an illustrative electronicdevice. In the example of FIG. 2, device 10 is a cover (or part of acover) for a tablet computer or other electronic equipment. Device 10may have housing structures formed from plastic, metal, glass, ceramic,carbon-fiber composites, fiberglass, and other fiber composites, fabricand other intertwined strands of material, and/or other materials. As anexample, device 10 may have components that are mounted within a housingbody formed from lower housing layer 24 and upper housing layer 26.Lower housing layer 24 may be formed from plastic, plastic with embeddedmicrofibers, or other materials. Upper housing layer 26 may be formedfrom fabric. The fabric of layer 26 may include strands of material thathave been intertwined using weaving techniques, knitting techniques,braiding techniques, or other techniques for intertwining strands ofmaterial.

The strands of material in the fabric of layer 26 may be polymerstrands, metal strands, glass strands, strands of material that includea core of one material (e.g., polymer) that is coated with one or moreadditional materials (e.g., a metal layer, a dielectric outer coating,etc.). The strands of material in layer 26 may be monofilaments ormulti-filament strands (sometimes referred to as yarn or thread).

Device 10 may include a keyboard (e.g., a computer keyboard for anassociated tablet computer, laptop computer, or other computingequipment). The keyboard may have an array of keys 20 that are coveredby fabric layer 26. Each key 20 may have a movable button member such askey cap 30 and an associated switch such as key switch 32. Key caps 30may be mounted in openings in a support structure such as key web 28(e.g., a plastic panel with rectangular openings and other openingsconfigured to receive respective key caps 30 or other button members).Key web 36 may supply structural support for fabric layer 26 and maytherefore form an internal frame for the upper housing wall of device10. Key switches 32 may be mounted on substrate 36. Substrate 36 may bea printed circuit board that contains metal traces for forming signalpaths to interconnect support circuitry 34 (e.g., one or more integratedcircuits) with key switches 32.

FIG. 3 is a cross-sectional side view of a portion of device 10. Asshown in FIG. 3, key cap 30 may be aligned with key switch 32 so thatkey switch 32 may be actuated when a user's finger (finger 40) pressesdownwards in direction 42 on the key formed from key cap 30 and switch32. Switch 32 may be a dome switch or other switch mounted on printedcircuit 36. Support structures 46 (e.g., a butterfly mechanism or otherhinge mechanism) may be used to provide support for key cap 30 and mayprovide a restoring force that biases key cap 30 upwards in direction 44when the user releases the key.

Fabric layer 26 may be attached to the upper surface of device 10 andmay cover key web 28 and the upper surfaces of key caps 30 in keys 20.Adhesive 48, injection-molded portions of key web 28, or other suitableattachment mechanisms may be used to attach portion 26-2 of fabric layer26 to key web 28 and to attach portion 26-1 of fabric layer 26 to keycaps 30. The key cap in each key may be surrounded by peripheralportions 26′ of fabric layer 26. If, for example, key caps 30 arerectangular, peripheral portions 26′ may have the shape of rectangularrings. The peripheral boundary portion 26′ of fabric layer 26 thatsurrounds each key 20 is preferably sufficiently flexible to allow keycaps 30 to travel freely both in outwards direction 44 and inwardsdirection 42 during use of the keyboard by a user.

If desired, the flexibility of fabric portions 26′ and/or the propertiesof other structures in device 10 may be adjusted during manufacturing.Equipment of the type that may be used in making these types ofadjustments to fabric layer 26 and other device structures is shown inFIG. 4.

As shown in FIG. 4, structures 52 (e.g., device components, partlyassembled devices such as fabric layer 26 and other structures of thetype shown in FIG. 3, and/or fully assembled devices 10) may beprocessed using equipment 50.

Equipment 50 may include equipment for applying heat to structures 52such as equipment 58. Equipment 58 may include a hot bar tool or othertool that produces heat to soften, melt, cure, or otherwise modifystructures 52. A hot bar tool may include a heated metal member that canbe placed into contact with a portion of structures 52. Heated embossingequipment (e.g., heated metal die structures that can be used to embossa desired pattern onto a layer of fabric or other material that iscompressed between the die structures) and/or other heated structuresmay be included in equipment 50.

Light-based tools 60 may also be used to process structures 52. Tools 60may include sources of light such as lasers, light-emitting diodes, andlamps. Tools 60 may emit ultraviolet light, visible light, and/orinfrared light. The light emitted by tools 60 may include wide areaillumination and/or focused beams. Light may be emitted continuously(e.g., using a continuous wave laser) or may be emitted in pulses (e.g.,to perform laser ablation operations). Tools 60 may emit laser pulseshaving durations of 10⁻¹⁵-10⁻¹² seconds, 10⁻¹⁵-10⁻⁹ seconds, longer thanon picosecond, shorter than one picosecond, longer than one nanosecond,shorter than one nanosecond, between one femtosecond and onemillisecond, or other suitable durations. Short pulses may have highenergy densities and may be suitable for ablating (vaporizing) polymersand other materials without melting nearby structures. Short pulses,longer duration pulses, and/or continuous wave light beams may be usedin softening and/or melting polymers and other materials.

If desired structures 52 may be processed using additional tools 56 suchas machining tools (e.g., a milling machine, drill, grinding equipment,etc.), molding tools (e.g., plastic injection molding tools and otherequipment for molding plastic), tumbling equipment (e.g., equipment forsoftening fabric), chemical baths (e.g., for electroplating, formodifying the surfaces of structures 52, for etching, etc.), printingequipment (e.g., screen printing tools, inkjet printing tools, etc.),photolithographic tools, ovens, cutting tools, and/or other equipmentfor processing structures 52.

Assembly tools 54 may be used in attaching components together to formassemblies and may be used in joining components and/or assemblies toform finished devices. Assembly tools 54 may include manually controlledtools and computer-controlled robotic assembly equipment.

The material that forms layer 26 of device 10 may include plastic,metal, glass, other materials, and/or combinations of these materials.As shown in the example of FIG. 5, layer 26 may be formed from strandsof material such as strands 64 that have been embedded within a bindersuch as binder 62 (e.g., a cured polymer resin). As shown in FIG. 6,layer 26 may be embossed or molded to form protrusions such asprotrusion 68 and recesses such as recess 66. Strands 64 may be embeddedwithin binder 62 and/or may include portions that are uncoated with anybinder material. Portions of layer 26 may also be free of strands 64.Embossing or molding equipment for processing layer 26 may includestructures that apply a desired pattern (e.g., a desired surfacetopology) to layer 64 under heat and pressure (as an example).

In the example of FIG. 7, layer 26 is a fabric layer having strands 72(e.g., yarn or other strands) that have been intertwined (e.g., woven,knitted, braided, etc.) and coated on one side with coating layer 74.Coating layer 74 may be, for example, a polymer coating that forms abacking layer for the fabric layer formed from strands 72. After formingthe fabric layer from strands 72 and after coating the underside of thefabric layer with coating layer 74, a pulsed laser or other light sourcemay be used to remove a portion of coating layer 74 and a portion of oneor more strands 72 (e.g., laser ablation may be used to ablate coating74 and strands 72 to form recess (opening) 70.

As shown in FIG. 8, layer 26 may include one or more layers of materialsuch as layers 78. Layers 78 may be formed from foam, solid plastic orother solid materials, fabric, etc. Layers such as illustrative layer 26of FIG. 8 may be embossed, molded, cut, machined, processed with a laser(e.g., a laser ablation tool), or otherwise processed using equipment 50of FIG. 4.

FIG. 9 is a diagram of an illustrative hot bar tool. Tool 58 includes aheated member such as heated member 82 (e.g., a heated metal member).Computer-controlled positioner 80—may adjust the position of heatedmember 82. In the example of FIG. 9, heated member 82 has been placed incontact with the surface of layer 26 and has applied heat to portion 90of layer 26 (e.g., to cure adhesive in portion 90, to soften or meltplastic or other materials in portion 90, etc.).

FIG. 10 is a diagram of an illustrative light-based tool such as a lasertool. Tool 60 includes laser 86. Laser 86 produces laser beam 88.Computer-controlled positioner 84 may adjust the position of laser 86and thereby adjust the position of laser beam 88. If desired, ancillarybeam steering structures such as adjustable mirrors may be used toadjust the position of laser beam 88. Laser beam 88 may be a pulsedlaser beam that ablates material from layer 26 in the region that isexposed to beam 88 (e.g., portion 90) or may be a continuous wave laserbeam. Portion 90 may be heated to soften or melt portion 90 of layer 26,may be ablated to remove portion 90, may be cured by the light and/orheat associated with beam 88, or may otherwise by processed by exposureto light 88.

It may be desirable to use equipment 50 to process portion 26′ of layer26 to adjust the stiffness of portion 26′ of layer 26. Adjustments tothe stiffness of layer 26 may be made to ensure that the amount of forceassociated with depressing and releasing each key 20 (i.e., the “clickfeel” of key 20) is within desired limits. For example, portion 26′ (orother portions of layer 26) may be processed using tool 60 to applylaser light 88, using tool 58 to apply heat, or using other equipment 50to modify portion 26′.

In the illustrative configuration of FIG. 11, region 90 on upper surface26T of portion 26′ is being processed (e.g., by exposure to laser light88, heat, etc.) without modifying lower surface 26B. Portion 90 may forma melted region, a recess (e.g., a groove or pit that has been formed byremoving material using laser ablation techniques) or other processedportion in layer 26.

In the illustrative configuration of FIG. 12, processed portion 90extends through portion 26′ of layer 26. Processed portion 90 of FIG. 12may be, for example, an opening such as a circular or rectangular holeor a melted region that passes from upper (outer) surface 26T to lower(inner) surface 26B.

FIG. 13 shows an illustrative processing arrangement for portion 26′ inwhich region 90 on lower surface 26B of portion 26′ is being processed(e.g., by exposure to laser light 88, heat, etc.) without modifyingupper surface 26T. As with the arrangement of FIG. 11, portion 90 ofFIG. 13 may form a melted region, a recess (e.g., a groove or pit thathas been formed by removing material using laser ablation techniques),or other processed portion in layer 26.

If desired, equipment 50 may be used to form an array of processed areasin the upper surface, lower surface, and/or both upper and lowersurfaces of layer 26, as shown by portions 90 of FIG. 14. FIG. 15 is adiagram showing how processed region 90 may include parallel lines(e.g., grooves, slots, etc.). In the example of FIG. 16, processedregion 90 has the shape of a serpentine line. Line-shaped regions may beformed by exposing the entire line to laser light at the same time or byscanning a focused laser beam across the surface of layer 26. FIG. 17shows how processed region 90 may include two sets of interleaved lines.Other patterns for processed region(s) 90 may be used when processinglayer 26, if desired.

Portions of layer 26 adjacent to keys 20 may be processed to adjust thestiffness of keys 20. In particular, each key 20 may be surrounded by arectangular border or other border (i.e., peripheral portion 26′ oflayer 26). The stiffness of keys 20 can be adjusted by selectivelyprocessing borders 26′ using equipment 50. For example, testing may beperformed on each key 20 in a keyboard in device 10 to determine whichkeys are stiffer than desired. The border 26′ of each overly stiff keymay then be processed using a laser ablation tool. The laser ablationtool (e.g., tool 60 of FIG. 10) may remove selected portions of stiffborder regions 26′ to reduce the stiffness of these regions and therebyreduce the stiffness of the keys that are associated with these regionsto appropriate levels.

Some or all of peripheral region 26′ surrounding keys 20 may beprocessed. Illustrative processing patterns (patterns for processedregions 90 adjacent to keys 20) are shown in FIGS. 18, 19, 20, 21, 22,and 23. Processed regions 90 may include portions of layer 26 that havebeen processed on the outer surface of layer 26, portions of layer 26that have been processed on the inner surface of layer 26, portions oflayer 26 that have been processed to form through holes (e.g.,perforations) that pass between the outer and inner surfaces of layer26, portions of layer 26 from which material has been removed by laserablation, portions of layer 26 that have been melted or cured, etc.

In the example of FIG. 18, region 26′ has a rectangular (square) shapewith four sides and four corners. Processed regions 90 overlap thecorners. In the FIG. 18 example, all four corners have been processed.Fewer corners of region 26′ may be processed if desired. All fourcorners may be processed in the same way (laser beam power, laser beampulse duration, etc.) or different corners may be processed differently.

FIG. 19 shows how processed region 90 may include a series of elongatedparallel regions. These regions may be include grooves that pass partlythrough layer 26 and/or slots (elongated openings) that pass entirelythrough layer 26. The parallel regions of FIG. 19 may run parallel tothe outline of border 26′ and may be continuous (e.g., the lines may begrooves having rectangular ring shapes) or may be discontinuous.

FIG. 20 shows how regions 90 may be grooves or slots that extendradially outward from the center of key 20. In the FIG. 21 example,regions 90 have the shape of vertically and horizontally orientedrectangles. FIG. 22 shows how regions 90 may have circular or ellipticalshapes. Regions 90 of other shapes (e.g., triangles, pentagons,hexagons, etc.) may also be used. In FIG. 23, regions 90 include acombination of shapes such as rectangles and circles. Other combinationsof shapes (lines with curved portions, lines with straight portions,shapes with combinations of curved and/or straight edges, etc.) may alsobe used.

By adjusting the stiffness of fabric 26 adjacent to keys 20 (e.g., inperipheral ring-shaped regions such as regions 26′ that run along theedges of key caps 30), the performance of keys 20 can be adjusted duringmanufacturing to overcome variations in stiffness (e.g., fabricstiffness variations in scenarios in which layer 26 includes a fabriclayer). Other properties of a fabric layer or a layer 26 of othermaterials may also be modified to adjust characteristics such asstiffness, height, density, porosity, smoothness, reflectivity, etc.

FIG. 24 is a flow chart of illustrative steps involved in forming adevice such as device 10. The processing operations of FIG. 24 includeprocessing operations on structures 52 using equipment 50 (FIG. 4). Withone suitable arrangement, which is described herein as an example,device 10 includes a keyboard with keys 20 and device structures 52include a layer of fabric such as fabric 26 that overlaps keys 20.Fabric 26 may include woven strands of material such as woven polyesteryarn (e.g., 50D/36F yarn) or other intertwined strands of material. Apolymer backing layer (e.g., a polyurethane coating) and, if desired, alayer of adhesive, may be applied to the inner surface of fabric 26(see, e.g., layer 74 of FIG. 7). Other types of electrical devices anddevice structures may be processed using equipment 50 if desired. Theuse of equipment 50 to process a layer of material such as layer 26 thatincludes woven polymer yarn is merely illustrative.

At step 100, device 10 may be fully or partly assembled. For example,key switches 32 and other circuitry may be mounted on printed circuit36, key caps 30 may be mounted in openings in a key cap support layersuch as key web 28 may be aligned with key switches 32, and a coveringstructure such as fabric layer 26 may be attached to the upper surfaceof key caps 30 and key web 28.

All or part of device 10 may be tested at step 102. For example, keyperformance can be measured using robotic test equipment that pressesand releases each key 20 while gathering force measurements. These forcemeasurements can then be compared to predetermined desired force rangesor other predetermined performance criteria. In response to determiningthat keys 20 (or other tested device structures) satisfy the performancecriteria, assembly operations for device 10 can be completed at step108.

In response to determining that one or more keys 20 (or other testeddevice structures) do not satisfy the performance criteria, reworkoperations can be performed on device structures 52 at step 104. Ifportions of layer 26 such as portions 26′ adjacent to keys 20 are toostiff, these portions can be processed to reduce the stiffness toacceptable levels. For example, a portion of the yarn and backing layermaterial in fabric layer 26 may be selectively removed via laserablation (e.g., using patterns of the type shown in FIGS. 18, 19, 20,21, 22, and 23). Through holes (perforations) or recesses that pass onlypartway through layer 26 may be formed in processed areas 90.

The presence of the laser ablated regions may locally weaken fabric 26.By making regions 26′ of fabric 26 weaker in this way, the stiffness ofregions 26′ and therefore the stiffness of the keys associated withthese regions may therefore be reduced. After modifying regions 26′during the processing operations of step 104, additional testing may beperformed at step 102. If the tests are unsatisfactory, additionalrework operations may be performed at step 104. If the tests aresatisfactory, assembly may be completed at step 108.

The foregoing is merely illustrative and various modifications can bemade by those skilled in the art without departing from the scope andspirit of the described embodiments. The foregoing embodiments may beimplemented individually or in any combination.

What is claimed is:
 1. An electronic device, comprising: first andsecond keys; and a layer of fabric that overlaps the first and secondkeys, wherein the layer of fabric has an opening that extends at leastpartway through the fabric, wherein the opening is located between afirst region of the fabric that overlaps the first key and a secondregion of the fabric that overlaps the second key, wherein the openinghas a perimeter, and wherein the fabric extends around the entireperimeter of the opening.
 2. The electronic device defined in claim 1wherein the first and second keys each comprise a movable member.
 3. Theelectronic device defined in claim 2 wherein the layer of fabriccomprises intertwined strands of material.
 4. The electronic devicedefined in claim 3 wherein the layer of fabric comprises a laser ablatedregion from which a portion of the layer of fabric has been removed bylaser ablation, and wherein the laser ablated region is located betweenthe first and second regions.
 5. The electronic device defined in claim4 wherein the intertwined strands of material comprise intertwinedpolymer strands.
 6. The electronic device defined in claim 5 whereineach strand is a yarn containing multiple polymer filaments.
 7. Theelectronic device defined in claim 6 wherein the intertwined strands ofmaterial comprise woven fabric.
 8. The electronic device defined inclaim 7 further comprising a polymer coating on the woven fabric,wherein the polymer coating is located on the first and second regionsof the layer of fabric, and wherein some portions of the laser ablatedregion are free of the polymer coating.
 9. The electronic device definedin claim 7 wherein the opening comprises a laser-ablated opening thatpasses only partway through the woven fabric.
 10. The electronic devicedefined in claim 7 wherein the opening comprises a laser-ablated openingthat passes completely through the woven fabric.
 11. The electronicdevice defined in claim 10 wherein the opening is part of an array ofopenings that surround the first key.
 12. A keyboard, comprising: aplurality of keys mounted to a printed circuit, wherein each of the keyshas a key cap with a first perimeter; and a fabric that covers the keys,wherein each of the keys is surrounded by a respective border region inthe fabric, wherein the border region has four sides that form a secondperimeter that is larger than the first perimeter, and wherein each ofthe four sides comprises an array of openings distributed along thesecond perimeter, wherein the openings extend at least partway throughthe fabric to reduce the stiffness of that border region and the keysurrounded by that border region.
 13. The keyboard defined in claim 12wherein the fabric has stiff regions that overlap the keys, and whereineach array of openings is located between the stiff regions of thefabric.
 14. The keyboard defined in claim 13 wherein the openings extendonly partway through the fabric.
 15. The keyboard defined in claim 13wherein the openings pass completely through the fabric.
 16. Thekeyboard defined in claim 13 wherein the border region of the fabricincludes laser ablated yarn.
 17. An electronic device cover, comprising:keys having key caps; and a fabric layer having stiff regions thatoverlap the keys and flexible border regions that surround the stiffregions, wherein the flexible border regions of the fabric include laserprocessed portions with openings that extend at least partway throughthe fabric, wherein the openings do not overlap the key caps.
 18. Theelectronic device cover defined in claim 17 wherein the fabric layercomprises woven fabric.
 19. The electronic device defined in claim 18wherein the woven fabric comprises polymer strands and wherein the laserprocessed portions comprise laser ablated portions of the polymerstrands from which polymer has been removed.
 20. The electronic devicedefined in claim 18 wherein each stiff region has four sides, andwherein the openings comprise laser ablated recesses in the woven fabricthat surround each stiff region on all four sides.
 21. The electronicdevice defined in claim 17 wherein the stiff regions of the fabric arecoated with a polymer coating that does not extend into the flexibleborder regions.